Lincomycin analogs

ABSTRACT

Compounds of the formula: ##STR1## are disclosed, wherein R 1  taken independently is hydrogen; R 2  taken independently is the moiety ##STR2## wherein Ac is carboxacyl or an acyl group of formula: ##STR3## wherein Z is hydrogen, lower alkyl or a protective group removable by hydrogenolysis; R 5  is lower alkyl; R 1  and R 2  when together are the divalent group; ##STR4## wherein Z and R 5  are as defined above; R 3  is hydrogen when R 1  and R 2  are taken together and is a monovalent thio group of formula: ##STR5## located in the 7(S)-position when R 1  and R 2  are taken independently, A represents hydrogen or hydroxyl, B represents hydrogen or hydroxyalkyl, n is the integer 0 when B is hydroxyalkyl and n is an integer of 0 to 1, inclusive, when B is hydrogen, X is oxygen .[.or sulfur.]., D is the acyl radical of a lower hydrocarbon carboxylic acid; R 4  is lower alkyl and Y is carboxacyl or hydrogen. 
     Disclosed also are methods of making and using the novel compounds of the invention, which are useful intermediates in the chemical synthesis of useful antibacterial lincomycin analogs. Certain of the compounds of the invention are also active as antibacterial agents.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention concerns α-thiolincosaminide derivatives; theirpreparation and uses as intermediates in the chemical synthesis oflincomycin analogs. More particularly, the invention concerns novelalkyl N-acyl-6,7-aziridino-6-deamino-7-deoxy-α-thiolincosaminides andnovel alkyl 7(S)-acyloxythioalkyl-α-thiolincosaminides, theirpreparation and use.

2. Description of the Prior Art

7-0-Alkyl-substituted-α-thiolincosaminides and their preparation fromalkyl N-acyl-6,7-aziridino-α-thiolincosaminides are described in U.S.Pat. No. 3,702,322.

Iranian Pat. No. 10,460 of Aug. 15, 1972 (copending U.S. applicationSer. No. 237,129; filed Mar. 22, 1972, now Pat. No. 3,790,560) describesalkyl 7-deoxy-7-mercaptoalkylthio-α-thiolincosaminides, theirpreparation by sulfidolysis of appropriate6,7-aziridino-6-deamino-7-deoxy-α-thiolincosaminides and theirconversion to corresponding lincomycin analogs.

Iranian Pat. No. 10,395 of Aug. 15, 1972 (copending U.S. applicationSer. No. 198,990; filed Nov. 15, 1971, now abandoned) discloses alkyl7-deoxy-α-thiolincosaminides having a variety of substituted thio groupsin the 7(S)-position, such as for example, alkylthio, hydroxyalkylthioand acetoxyalkylthio groups. Also disclosed are preparative proceduresfor such compounds, which comprises sulfidolysis of appropriate6,7-aziridino-6-deamino-7-deoxy-α-thiolincosaminides and use of theproduct compounds to prepare lincomycin analogs.

Iranian Pat. No. 10,407 of Aug. 15, 1972 (copending U.S. applicationSer. No. 199,046; filed Nov. 15, 1971, now U.S. Pat. No. 3,767,649)discloses in particular the compound methylN-acetyl-2,3,4-tri-0-acetyl-7(S)-[3-(3-acetoxypropylthio)propylthio]-7-deoxy-α-thiolincosaminideand lincomycin analogs thereof. The patent teaches preparation of theparticular compound by addition of trimethylene sulfide to methylN-acetyl-2,3,4-tri-0-acetyl-6,7-aziridino-6-deamino-7-deoxy-α-thiolincosaminide.

In general, the compounds of the present invention are intermediates forpreparing many of the compounds disclosed in the above described Iranianpatents. None of the intermediate compounds of my present invention canbe prepared by the process set forth in the above described patents.

The process of the invention comprises, broadly, the sulfidolysis ofcertain alkyl 6,7-aziridino-6-deamino-7-deoxy-α-thiolincosaminideemploying a particular class of cyclic sulfur compounds. The products ofthe process are obtained in very high yields, about twice the yields ofsulfidolated products obtained in those processes of Iranian Pat. Nos.10,395; 10,407 and 10,460, supra.

Since the 7(S)-S-substituted compounds obtained by the process of thisinvention are quantitatively converted upon hydrolysis to certain ofthose sulfidolated products of said Iranian Patents, the process of thepresent invention and the products thereof offer a commerciallyadvantageous means of preparing 7(S)-thiosubstituted lincomycins.

Moreover, the process of the invention provides a method of obtainingintermediate compounds useful for preparing a class of antibacterialagents not previously known, or preparable by previously known methods;i.e., the alkylN-(L-2-pyrrolidincarboxyacyl)-7-deoxy-7(S)-(acetoxymethoxy)-alkylthio-.alpha.-thiolincosaminides,and the alkylN-(L-2-pyrrolidinecarboxacyl)-7-deoxy-7(S)-acetoxymethylthio)-alkylthio-.alpha.-thiolincosaminides.

Alkyl N-carboxacyl-6,7-aziridino-6-deamino-7-deoxy-α-thiolincosaminideshave also been disclosed prior hereto; see for example, U.S. Pat. Nos.3,671,647 and 3,702,332; Iranian Pat. Nos. 10,395 and 10,460. However,attempts to obtain the alkylN-(L-2-pyrrolidinecarboxacyl)-6,7-aziridino-6-deamino-7-deoxy-α-thiolincosaminidesof the invention by methods taught in the above references for preparingthe N-carboxacyl analogs, i.e., by N-acylation of the aziridino with anL-2-pyrrolidine-carboxylic acid or the corresponding 1-alkyl substitutedL-2-pyrrolidinecarboxylic acid have met with failure prior hereto. Bythe novel process disclosed herein, alkylN-(1-carbobenzoxy-4-alkyl)-6,7-aziridino-6-deamino-7-deoxy-α-thiolincosaminidesare prepared, from which the corresponding useful 1'-hydrogen and1'-alkyl analogs are obtained.

SUMMARY OF THE INVENTION

The invention comprises compounds of the formula: ##STR6## wherein R₁when taken independently represents hydrogen; R₂ when takenindependently represents the monovalent moiety ##STR7## wherein Ac isselected from carboxacyl and an acyl radical of formula: ##STR8##wherein Z is selected from hydrogen, lower alkyl and a protective groupremovable by hydrogenolysis; R₅ is lower alkyl; R₁ and R₂ when takentogether form the divalent moiety of formula: ##STR9## wherein Z and R₅are as defined above; R₃ is hydrogen when R₁ and R₂ are taken togetherand when R₁ and R₂ are taken independently, R₃ is a monovalent thiogroup in the 7(S)-position having the formula: ##STR10## wherein A isselected from hydrogen and hydroxyl, B is selected from hydrogen andhydroxyalkyl, n is the integer 0 when B is hydroxyalkyl and n is aninteger of from 0 to 1, inclusive, when B is hydrogen, X is .[.selectedfrom.]. oxygen .[.and sulfur.]., D is an acyl radical of a lowerhydrocarbon carboxylic acid; R₄ represents lower alkyl; and Y isselected from carboxacyl and hydrogen.

The wavy line joining R₅ to the body of the molecule as shown in formula(I) indicates that the group R₅ may be in either the cis (below theplane of the nitrogen-containing ring) or trans (above the plane of thenitrogen-containing ring).

The wavy line joining the methyl group and R₃ to the carbon atom atposition number 7 in the formula (I) indicates that certain of thecompounds (I) exist in both 6(R), 7(R) and 6(R), 7(S) epimeric forms,i.e., those compounds (I) wherein R₁ and R₂ are taken together have thestructure: ##STR11## The term "carboxacyl" as used throughout thespecification and claims means the acyl radical of a hydrocarboncarboxylic acid or of a hydrocarbon carboxylic acid substituted with aninert group. Preferred as carboxacyl groups are the acyl radicals ofhydrocarbon carboxylic acids and inert group substituted hydrocarboncarboxylic acids having from 2 to about 18 carbon atoms, inclusive, intheir structure. Representative of such carboxacyl groups are those offormula: ##STR12## wherein E is hydrocarbyl of from 1 to about 17 carbonatoms, inclusive, or hydrocarbyl of from 1 to 17 carbon atoms,inclusive, wherein a hydrogen atom has been replaced with an inertsubstituent group. Illustrative of acyl radicals of a hydrocarboncarboxylic acid wherein E is hydrocarbyl are the acyl radicals of (a)saturated or unsaturated, straight or branched chain aliphaticcarboxylic acids, for example, acetic, propionic, butyric, isobutyric,tert-butylacetic, valeric, isovaleric, caproic caprylic, decanoic,dodecanoic, lauric, tridecanoic, myristic, pentadecanoic, palmitic,margaric stearic, acrylic, crotonic, undecylenic, oleic, hexynoic,heptynoic, octynoic acids and the like; (b) saturated or unsaturated,alicyclic carboxylic acids, for example, cyclobutanecarboxylic acid,cyclopentanecarboxylic acid, cyclopentenecarboxylic acid,methylcyclopentenecarboxylic acid, cyclohexanecarboxylic acid,dimethylcyclohexenecarboxylic acid, dipropylcyclohexanecarboxylic acid,and the like; (c) saturated or unsaturated, alicyclic aliphaticcarboxylic acids, for example, cyclopentaneacetic acid,cyclopentanepropionic acid, cyclohexanebutyric acid,methylcyclohexaneacetic acid, and the like; (d) aromatic carboxylicacids, for example, benzoic acid, toluic acid, naphthoic acid,ethylbenzoic acid, isobutylbenzoic acid, methylbutylbenzoic acid, andthe like; and (e) aromaticaliphatic carboxylic acids, for example,phenylacetic acid, phenylpropionic acid, phenylvaleric acid, cinnamicacid, phenylpropionic acid, and naphthylacetic acid, and the like.

The term "hydrocarbon carboxylic acid substituted with an inert group"is used herein to mean a hydrocarbon carboxylic acid wherein one or morehydrogen atoms attached directly to a carbon atom have been replacedwith a group inert to reaction under the conditions hereinafterdescribed for preparing compounds (I) of the invention. Illustrative ofsuch substituent groups are halo-, nitro-, hydroxy-, amino-, cyano-,thiocyano-, or alkoxy-groups. Illustrative of halo-, nitro-, hydroxy-,amino-, cyano-, thiocyano- and alkoxy-substituted hydrocarbon carboxylicacids re mono-, di-, and trichloroacetic acid; α- and β- chloropropionicacid; α- and γ-bromobutyric acid; α- and δ iodovaleric acid; mevalonicacid; 2- and 4-chlorocyclohexanecarboxylic acid; shikimic acid;2-nitro-1-methylcyclobutanecarboxylic acid;1,2,3,-4,5,6-hexachlorocyclohexanecarboxylic acid;3-bromo-2-methylcyclohexanecarboxylic acid; 4- and5-bromo-2-methylcyclohexanecarboxylic acid; 5- and6-bromo-2-methylcyclohexanecarboxylic acid;2,3-dibromo-2-methylcyclohexanecarboxylic acid;2,5-dibromo-2-methylcyclohexanecarboxylic acid;4,5-dibromo-2-methylcyclohexanecarboxylic acid;5,6-dibromo-2-methylcyclohexanecarboxylic acid;3-bromo-3-methylcyclohexanecarboxylic acid;6-bromo-3-methylcyclohexanecarboxylic acid;1,6-dibromo-3-methylcyclohexanecarboxylic acid;2-bromo-4-methylcyclohexanecarboxylic acid;1,2-dibromo-4-methylcyclohexanecarboxylic acid;3-bromo-2,2,3-trimethylcyclopentanecarboxylic acid;1-bromo-3,5-dimethylcyclohexanecarboxylic acid; homogentisic acid; o-,m-, and p-chlorobenzoic acid; anisic acid; salicylic acid;p-hydroxybenzoic acid; β-resorcylic acid; gallic acid; veratric acid;trimethoxybenzoic acid; trimethoxycinnamic acid; 4,4'-dichlorobenzilicacid; o-, m-,, and p-nitrobenzoic acid; cyanoacetic acid; 3,4- and3,5-dinitrobenzoic acids; 2,4,6-trinitrobenzoic acid; thiocyanoaceticacid; cyanopropionic acid; lactic acid; ethoxyformic acid (ethylhydrogen carbonate); butyloxyformic acid; pentyloxyformic acid;hexyloxyformic acid; dodecyloxyformic acid; hexadecyloxyformic acid andthe like.

The term "protective group removable by hydrogenolysis" as used hereinmeans a group inert to acylation but readily removable byhydrogenolysis. Such groups are well known in the art, and areillustrated by trityl, diphenyl-(p-methoxyphenyl)methyl,bis-(p-methoxyphenyl)-phenylmethyl, benzyl, or p-nitrobenzyl andhydrocarbyloxycarbonyl groups. Examples of the latter aretertiary-butoxycarbonyl; benzyloxycarbonyl groups of the formula:##STR13## wherein W is hydrogen, nitro, methoxy, chloro, or bromo, forexample, carbobenzoxy, p-nitrocarbobenzoxy, p-bromo-, andp-chlorocarbobenzoxy-; and phenyloxycarbonyl groups of the formula:##STR14## wherein W₁ is hydrogen, allyl, or alkyl of not more than 4carbon atoms, such as phenyloxycarbonyl, p-tolyloxycarbonyl,p-ethylphenyloxycarbonyl, and p-allylphenyloxycarbonyl and the like.

The term "lower alkyl" is employed in its usual sense as meaning alkylof from 1 to about 8 carbon atoms, inclusive, such as methyl, ethyl,propyl, butyl, pentyl, hexyl, heptyl, octyl and isomeric forms thereof.

The term "R₁ and R₂ when taken together" means R₁ and R₂ together mayconstitute a single group, and when so taken will represent the abovedescribed divalent moiety having its valencies satisfied by covalentbonds to carbon atoms at positions 6 and 7, respectively, in the formula(I).

The term "hydroxyalkyl" as used herein means alkyl as defined abovewherein a hydrogen atom has been replaced by a hydroxyl group.Illustrative of hydroxyalkyl are hydroxyalkyl having from 1 to 6 carbonssuch as hydroxymethyl, hydroxyethyl, hydroxypropyl, hydroxybutyl,hydroxypentyl and hydroxyhexyl.

The term "acyl radical of a lower hydrocarbon carboxylic acid" means anacyl radical of a hydrocarbon carboxylic acid as defined above, havingfrom 1 to about 8 carbon atoms, inclusive.

One skilled in the art will appreciate that those compounds (I) whereinA or B in the group R₃ are other than hydrogen may exist in both D- andL- diasteroisomeric forms. It is to be understood that the formula (I)above includes both the D- and L- diastereoisomers.

Compounds (I) of the invention are useful intermediates in the chemicalsynthesis of known lincomycin analogs which are antibacterial agents.The invention also comprises methods of preparing and using thecompounds (I) of the invention. These methods of preparation and usewill be described in greater detail hereinafter.

DETAILED DESCRIPTION OF THE INVENTION

The process of the invention is carried out according to the followingprocedures.

PROCESS A

Those compounds (I) of the invention wherein Z (if present) isspecifically a protective group removable by hydrogenolysis or loweralkyl and R₃ is specifically the above described thio group, i.e., Acompound of the formula: ##STR15## wherein A, B, X, D, n, R₄ and Y areas previously defined; and Ac₁ is carboxacyl or an acyl radical of theformula: ##STR16## wherein R₅ is as defined above and G is a protectivegroup removable by hydrogenolysis or lower alkyl; are readily preparedby bringing together the corresponding alkylN-acyl-6,7-aziridino-6-deamino-7-deoxy-α-thiolincosaminide (III) with asulfur compound of the formula: ##STR17## wherein A, B, X and n have themeanings previously ascribed to them, and an anhydrous lower hydrocarboncarboxylic acid (V).

The reaction which occurs is conveniently illustrated by the schematicformula: ##STR18## wherein Ac₁, R₄, A, B, D, X, Y, n and the wavy linesare as defined above.

As illustrated in the above reaction scheme, the starting alkylN-acyl-6,7-aziridino-6-deamino-7-deoxy-α-thiolincosaminide (III)starting compound, i.e., a 6(R), 7(R)-form is converted to thecorresponding 7(S)-derivative, (i.e., L-threo configuration) as a resultof the inversion of the 7(R)-position in the 6(R), 7(R)-form during thecourse of the reaction.

The compounds (II) of the invention are useful intermediate compounds.Upon removal of acyl groups (Ac₁, D or Y when Y is carboxacyl) byhydrazinolysis, for example, by hydrazinolysis following the procedureset forth in U.S. Pat. No. 3,179,565, there is obtained thecorresponding compound of formula: ##STR19## wherein A, B, n, X and R₄are as defined above.

The compounds (VI) may be N-acylated with the mixed anhydride oftrans-propyl-hygric acid and monoisobutyl carbonate (obtained byreacting trans-propylhygric acid with isobutyl chloroformate) by themethod disclosed in U.S. Pat. No. 3,380,992, to obtain the corresponding7(S)-S-substituted lincomycins. The latter compounds are usefulantibacterial agents; see, for example, Iranian Pats. Nos. 10,395 and10,460, supra.

In carrying out the Process A of the invention as illustrated above,reactants (III), (IV) and (V) are brought together and admixed usingconventional apparatus and techniques. The reaction proceedssatisfactorily under a broad range of temperatures conditions, i.e.,within a range of from about 25° C. to about 180° C. Preferably, theprocess of the invention is carried out within a temperature range offrom about 60° C. to about 150° C. and most preferably within atemperature range of from about 80° C. to about 110° C. The proportionsof reactants (III), (IV) and (V) and not critical to the processreaction, but influence the yields of product compounds (II). Theproportions employed may be stoichiometric, i.e., substantiallyequimolar. Optimum yields are obtained by employing the acid reactant(V) in excess; i.e., in a proportion of at least 2 molar equivalents andpreferably within a range of from about 2 to 8 molar equivalents. Thesulfar compound (IV) reactant is advantageously employed in excess ofstoichiometric requirements, i.e., a molar excess and preferably in aproportion of at least 2 molar equivalents, and most preferably within arange of from about 2 molar equivalents to about 60 molar equivalents.

Advantageously, the above described reaction is carried out in thepresence of an inert organic solvent. An inert organic solvent isdefined for the purpose of this invention as an organic solvent whichwill at least partially solubilize the thiolincosaminide reactant (III)and which does not enter into or in any way adversely affect the desiredcourse of the reaction. Illustrative of inert organic solvents aredioxane, carbon tetrachloride, chlorform, methylene chloride, benzene,toluene, n-hexane and like organic solvents. Preferred as the organicsolvent is an excess of sulfur compound (IV) i.e., in a proportionbeyond that required for the above described reaction, provided saidsulfur compound (IV) meets the above criteria for solubilizing reactant(III) at the temperature selected for carrying out the process.

In general, the above described reaction is complete in from aboutone-quarter to about 24 hours, depending upon the nature of the groupsAc₁, A, B, D, X, and Y in the formulae (II) and (III). Completion of thereaction may be ascertained by conventional analytical procedures suchas, for example, by vapor-phase chromatography, thin-layerchromatography and like procedures which will indicate the disappearanceof starting compounds (III) and the appearance of the desired productcompounds (II).

Upon completion of the reaction, the compounds (II) of the invention arereadily separated from the reaction mixture by conventional procedures.For example, excess solvent and excess reactants (IV) and (V) areremoved by distillation to leave a residue of crude compounds (II).Purified compounds (II) of the invention are separated from the cruderesidue by well known techniques such as, for example, bycounter-current distribution, chromatography and solvent extractiontechniques followed by crystallization.

The acid reactant starting compounds of formula (V) in anhydrous form aswell known compounds. In general they may be characterized by theirhaving an acidity constant of at least about K_(a) = 1.7 × 10⁻⁵.Illustrative of anhydrous lower hydrocarbon carboxylic acids (V) are drylower alkanoic acids having 2 to 8 carbon atoms, inclusive, such asacetic acid, propionic acid and octanoic acid; arenoic acids having 7 to8 carbon atoms, inclusive, such as benzoic acid and toluic acid.Preferred as the anhydrous hydrocarbon carboxylic acid is glacial aceticacid.

The sulfur compound reactants of formula (IV) are generally well knowncompounds as is their preparation. Those compounds (IV) wherein A and Bare each hydrogen are the well known compounds 1,3-oxathiolane,1,3-dithiolane, 1,3-oxathiane and 1,3-dithiane. The hydroxy-substituteddithiane and the hydroxyalkyl-substituted dithiolanes are readilyprepared following the method of E. J. Corey, et al., Angewandte Chemie,International Edition (England), 4, 1075, (1965). In general, the methodcomprises reacting an appropriate hydroxyalkanedithiol withdimethoxymethane in the presence of boron fluoride. Thus, for example,employing 1,3-dimercapto-2-propanol as the startinghydroxy-alkanedithiol, there is obtained 5-hydroxy-1,3-dithiane.

Employing a hydroxyalkanedithiol of formula: ##STR20## wherein P is aninteger of 1 to 6; there is obtained a 4-hydroxyalkyl-1,3-dithianewithin the scope of the formula (IV). Illustrative of such4-hydroxyalkyl-1,3-dithiolanes are 4-hydroxymethyl-1,3-dithiolane,4-(2-hydroxyethyl)-1,3-dithiolane,4-(1-methyl-1-hydroxyethyl)-1,3-dithiolane,4-91,1-dimethyl-2hydroxyethyl)-1,3-dithiolane.4-(5-hydroxypentyl)-1,3-dithiolane and4-(6-hydroxyhexyl)-1,3-dithiolane, which are prepared from theappropriate hydroxyalkanedithiols of formula (VII).

Illustrative of the hydroxyalkanedithiols (VII) are1,2-dimercapto-3-propanol, 1,2-dimercapto-4-butanol,1,2-dimercapto-3-methyl-4-butanol, 1,2-dimercapto-5-pentanol,1,2-dimercapto-3,3-dimethyl-4-butanol, 1,2-dimercapto-6-hexanol,1,2-dimercapto-7-heptanol, and 1,2-dimercapto-8-octanol.

Hydroxy-substituted 1,3-oxathianes and hydroxyalkyl-substituted1,3-oxathiolanes within formula (IV) above are most convenientlyprepared by condensing an appropriate thiol-substituted alkanediol withformaldehyde (paraformaldehyde) in the presence of an acid catalyst suchas concentrated hydrochloric acid or p-toluenesulfonic acid. [method ofR. M. Roberts, et al., J. Org. Chem., 23 983 (1958)]. Employing as thethiolsubstituted alkanediols compounds of formula: ##STR21## wherein Qis an integer of from 1 to 7, there are obtained the corresponding5-hydroxyalkyl-1,3-oxathiolanes such as5-(2-hydroxyethyl)-1,3-oxathiolane, 5-(3-hydroxypropyl)-1,3-oxathiolane,5-(1,1-dimethyl-2-hydroxyethyl)-1,3-oxathiolane,5(5-hydroxypentyl)-1,3-oxathiolane, 5-(6-hydroxyhexyl)-1,3-oxathiolaneand the like. Compounds (VIII) are well known as illustrated by1-mercapto-2,4-butanediol, 1-mercapto-2,5-propanediol,1-mercapto-3,3-dimethyl-2,4-butanediol, 1-mercapto-2,7-heptanediol,1-mercapto-2,8-octanediol and the like.

Advantageously the sulfur reactant of formula (IV) employed in preparingthe novel compounds (I) of the invention is a mixture of substantiallyequal proportions of 5-hydroxy-1,3-oxathiane and5-hydroxymethyl-1,3-oxathiolane. Said mixture is obtained by thecondensation of 1-mercapto-2,3-propanediol with formaldehye according tothe method of R. M. Roberts, et al., supra, described above.

The use of the mixture of 5-hydroxy-1,3-oxathiane and5-hydroxymethyl-1,3-oxathiolane as the reactant (IV) in the Process A ofthe invention is a preferred embodiment resulting in a high yield of amixture of the corresponding compounds (II) of the invention. The highproduct yield mixture of compounds (II) so obtained comprisesspecifically a mixture of the appropriate alkylN-acyl-2,3,4-tri-O-acyl-7-deoxy-7(S)-(3-acetoxymethoxy-2-hydroxypropylthio)-60-thiolincosamideand the alkylN-acyl-2,3,4-O-acyl-7-deoxy-7(S)-(2-acetoxymethoxy-3-hydroxypropylthio)-60-thiolincosaminide.The individual components (II) of the above described product mixturemay be hydrazinolysed while in admixture, employing conventionaltechniques, such as the example the hydraziolysis prcedure set forth inU.S. Pat. No. 671,647, to give quantitative yields of the correspondingalkyl 7(S)-(2,3-hydroxypropylthio)-7-deoxy-60thiolincosaminide. Thelatter compound is a useful intermediate for preparing the correspondinglincomycin hydrochloride, a useful antibacterial agent; see Iranian Pat.No. 10,395 supra.

The starting aziridino compounds (III) wherein Ac₁ is specificallycarboxacyl are well known compounds, see for example, U.S. Pat. Nos.3,671,647; 3,702,322 and Iranian Pat. Nos. 10,395; 10,460.

Those starting aziridino compounds (III) wherein Ac₁ is specifically theacyl radical of a 4-alkyl-substituted L-2-pyrrolidinecarboxylic acid,i.e., a compound of the formula: ##STR22## wherein G has the meaningpreviously given and R₅, R₄, Y and the wavy lines have the meaningspreviously assigned to them, are novel compounds within the scope of theformula (I) given above. As demonstrated herein, the novel compounds(IX) are useful in preparing corresponding compounds (II) of theinvention, wherein R₃ is the described thio group.

PROCESS B

The novel compounds (IX) of the invention are prepared by N-acylating anappropriate alkyl 6,7-aziridino-6-deamino-7-deoxy-α-thiolincosaminide(X) will an appropriate mixed anhydride (XI). The reaction isconveniently illustrated by the schematic formula: ##STR23## wherein R₄,R₅, Y, G and the wavy lines have the meanings previously ascribed tothem; b is an integer of from 1 to 3.

The process illustrated above is carried out by admixture of thereactants (X) and (XI) in substantially equimolar proportions usingconventional apparatus and techniques of mixing. Critical to the processis maintenance of the reaction mixture at a temperature of from about-10° C. to 5° C. during the course of the reaction. The requiredtemperature is maintained by the use of conventional methods of coolingreaction mixtures.

Advantageously, the Process B is carried out in the presence of an inertorganic solvent as previously defined. Preferred solvents areacetonitrile, nitromethane, tetrahydrofuran and dimethylformamide andmost preferably acetonitrile. Advantageously, the thiolincosaminidereactant (X) is solubilized in an inert organic solvent prior toadmixture with mixed anhydride reactant (XI). In this preferredembodiment, the inert solvent employed to dissolve the thiolincosaminidereactant (X) is preferably an aliphatic alcohol having a molecularweight of at least about 60. Illustrative of such aliphatic alcohols areisopropyl alcohol, n-butyl alcohol, isobutyl alcohol, tert-butylalcohol, n-hexyl alcohol, cyclohexanol and like aliphatic alcohols.

Advantageously, the above reaction is also carried out in the presenceof an acid acceptor compound such as, for example, a tertiary aminecompound. Illustrative of tertiary amines employed herein aretriethylamine tripropylamine, tributylamine, tripentylamine,trihexylamine and the like.

The process of the above illustrated reaction for preparing compounds(IX) of the invention may be followed by conventional analytical methodssuch as, for example, thin layer chromatography which will show theappearance of the desired product compounds (IX). In general, thereaction is complete in form about 1 to 24 hours. Upon completion of thereaction, the desired compounds (IX) are readily separated from thereaction mixture by conventional techniques such as by evaporation ofsolvent, solvent extraction, chromatography, counter-currentdistribution and like methods.

The starting thiolincosaminide reactants (X) employed in the abovedescribed Process B are well known compounds as is their preparation;see, for example, U.S. Pat. Nos. 3,671,647 and 3,702,322. Mixedanhydride reactants of formula (XI) are for the most part well known,and are prepared by reacting an appropriate L-2-pyrrolidinecarboxylicacid or hydrochloride salt thereof of formula ##STR24## wherein G and R₅are as defined previously, with an appropriate alkyl chloroformate suchas, for example, ethyl chloroformate, isopropyl chloroformate, isobutylchloroformate and the like. The method of preparing compounds (XI) iswell known, and representative details are given, for example, inExample 2, part F-2 of U.S. Pat. No. 3,544,551. The startingL-2-pyrrolidinecarboxylic acids of formula (XII) are generally wellknown; see, for example, U.S. Pat. Nos. 3,475,407; 3,544,551 and3,574,186; copending U.S. application Ser. No. 220,389, filed Jan. 24,1972, now Pat. No. 3,753,859.

PROCESS C

Specific compounds (I) of the invention wherein R₃ is the previouslydescribed thio group, and Z represents hydrogen, i.e., compounds of theformula: ##STR25## wherein A, B, n, X, D, Y, R₄ and R₅ and the wavy lineto R₅ are as defined above; are prepared by hydrogenolysis of thecorresponding compound (II) wherein Z is specifically a protective groupremovable by hydrogenolysis. The hydrogenolysis is carried out by knownprocedures, for example, by the procedure set forth in U.S. Pat. No.3,380,992. The compounds (XIII) of the invention are useful intermediatecompounds. By known methods, for example, as set forth in U.S. Pat. No.3,366,624, the proline nitrogen in compounds (XIII) may be alkylated byreaction with an alkyl halide. Alternatively, the compounds (XIII) maybe reacted with an aldehyde or ketone and the resulting adducthydrogenated. In this manner, the compounds (X) of the invention providea method of preparing novel compounds (I) of the invention having thespecific formula: ##STR26## wherein R₆ is lower alkyl, A, B, n, X, D, Y,R₄, R₅ and the wavy line to R₅ are as defined previously.

The compounds (XIV) of the invention wherein Y is specificallycarboxacyl are readily hydrolyzed by conventional techniques such as,for example, by base hydrolysis to obtain the corresponding7-deoxy-7-hydroxyalkylthio lincomycins disclosed in copending U.S.application Ser. No. 199,046, filed Nov. 15, 1971, as usefulantibacterial agents.

The compounds (XIV) of the invention wherein Y is specifically hydrogenare preferred compounds (I) of the invention. They are preferred becausethey possess antibacterial properties similar to, for example, the7-deoxy-7(S)-alkylthio lincomycins disclosed in Iranian Pat. Nos. 10,395and 10,460, are useful for the same purposes as said7-deoxy-7(S)-substituted lincomycins, and are useful in the same manner.

PROCESS D

A preferred process for preparing the compounds (I) of the inventionhaving the specific formula: ##STR27## wherein A, B, X, R₄, R₅, Y, D, nand the wavy line are as previously defined and G represents lower alkylor a protective group removable by hydrogenolysis is carried out in athree-step procedure which comprises;

1. reacting together an apropriate aziridine of formula (X), supra, andan appropriate mixed anhydride of formula: ##STR28## wherein G and R₅are as defined above and b is an integer of from 1 to 3, inclusive; at atemperature of from about -10° C. to about 5° C.; (2.) warming thereaction mixture so obtained to a temperature of from about 25° C. toabout 180° C.; and (3.) adding to the warmed reaction mixture anappropriate sulfur compound of formula (IV) ##STR29##

Details for carrying out the procedure of step (1.), in the abovedescribed preferred Process D are those disclosed previously herein asProcess B.

Step (2.) of Process D is carried out upon the completion of thereaction occurring in step (1.), but without separating the intermediatecompound of formula (IX) from the reaction mixture. Preferably, thewarming of the reaction mixture in step (2.) is to a temperature withinthe range of from about 60° C. to about 150° C. and most preferablywithin the range of from about 80° C. to about 110° C.

Details of the procedure for carrying out step (2.) of the Process D arethose disclosed herein as Process A, which differs only in respect tothe specific starting aziridino reactant employed.

The preferred solvents, when employed in Process A differ from thosepreferred when employed in Process B. As expected, solvents employed inthe various steps of Process D may therefore advantageously differ. Insuch case a given solvent may be readily stripped and replaced, ifdesired, by conventional methods well known to one skilled in the art,between consecutive steps of the Process D.

PROCESS E

An alternate and preferred process for the preparation of compounds(XIII) of the invention which were described previously as having theformula: ##STR30## is carried out by modifying the Process D describedabove, wherein in the mixed anhydride (XI), G is specifically a groupremovable by hydrogenolysis.

The modification of Process D comprises in step (2.) therein, warmingthe reaction mixture of step (1.) to a temperature within the range offrom about 25° C. to about 50° C. and prior to step (3.) carrying out anintervening step (2A.). Step (2A.) comprises subjecting the warmedreaction mixture obtained in step (2.) to catalytic hydrogenation. Theprocedure of catalytic hydrogenation is carried out by conventional andwell known methods.

In general, such methods comprise adding a catalytic proportion of ahydrogenation catalyst to the reaction mixture and agitating thereaction mixture under a hydrogen gas atmosphere of from 1 to about 50atmospheres of pressure. The technique is well known; see for exampleU.S. Pat. No. 3,380,992, Example 2, part (C) for details of such ahydrogenation. Upon completion of the hydrogenation step, which isgenerally complete in about 3-24 hours, as evidenced by cessation ofhydrogen consumption, step (3.) of Process D is commenced. Preferablythe hydrogenated mixture is first filtered to remove catalyst residuebefore proceeding to said step (3.).

The above described Processes D and E are particularly advantageousbecause they provide a method for the continuous production of thedesired compounds (XIII) and (XV) from the basis aziridino (X) withouthaving to isolate the appropriate intermediates which have the formula(IX). This is an important advantage for a number of reasons, forexample, certain of the intermediates formed, particularly the alkylN-(1-alkyl-4-propyl-L-prolyl)-6,7-aziridino-6-deamino-7-deoxy-α-thiolincosaminidesand the alkylN-(L-2-pyrrolidinecarboxacyl)-6,7-aziridino-6-deamino-7-deoxy-α-thiolincosaminidesare difficult to separate as pure materials in high yields. Thecontinuous methods of Processes D and E therefore provide in theseinstances the most practical processes from a commercial viewpoint.

The following preparations and examples describe the manner and processof making and using the invention and set forth the best modecontemplated by the inventor of carrying out the invention but are notto be construed as limiting.

Preparation 1. 5-Hydroxy-1,3-oxathiane and5-hydroxymethyl-1,3-oxathiolane

A mixture of 200 grams (1 molar equivalent) of 2,3-dihydroxypropanethiol(α-thioglycerol), 55.6 grams (1 molar equivalent) of paraformaldehyde,1.0 gram of p-toluenesulphonic acid, and 750 ml. of benzene is heated inan oil-bath at 100° C in a Dean-Stark water-separator apparatus for 12hours while being continually stirred. At the end of this period,benzene is removed from the reaction mixture by distillation atatmospheric pressure and then under 7 mm. of mercury. The residue issubjected to distillation under high-vacuum, and gives as a residue acolorless liquid, b.p. 66°-67° C. at 0.5 mm. of mercury, which is amixture of 5-hydroxy-1,3-oxathiane and 5-hydroxy-methyl-1,3-oxathiolanein about equal proportions. Structure of the mixture components isconfirmed by vapor phase chromatography and mass spectral analysis. Thisproduct mixture was demonstrated to be free of thio starting material bythe method of Feigl, "Spot Tests in Organic Analysis," 7th English Ed.,(1966), Elsevier Publ. Co., N.Y., N.Y., pps. 219-220.

Anal. Calcd. for: C₄ H₈ O₂ S (percent): C, 39.98; H, 6.71; S, 26.69.

Found (percent): C, 39.64; H, 6.83; S, 27.07

EXAMPLE 1 MethylN-[1-carbobenzoxy-trans-4-propyl-L-prolyl]-6(R),7(R)-aziridino-6-deamino-7-deoxy-α-thiolincosaminide.

To a solution of 2.91 grams (1 molar equivalent) of1-carbobenzoxy-trans-4-propyl-L-proline (prepared by N-carboxylation oftrans-4-propyl-L-proline, (prepared according to the method of copendingU.S. application Ser. No. 220,389, filed Jan. 24, 1972) in 100 ml. ofanhydrous acetonitrile, there is added 1.11 grams of triethylamine (1.53ml.; 1.1 molar equivalents) with stirring. The stirred solution iscooled to .[.315.]. .Iadd.-5°.Iaddend. C. in an ice-methanol bath. Tothe resulting mixture 1.36 grams (1.30 ml.; 1 molar equivalent) ifisobutyl chloroformate is added and the mixture stirred for 20 minuteswhile maintaining the temperature at circa -5° C. A precipitate oftriethylammonium chloride is formed.

A suspension of 2.35 grams (1 molar equivalent) of methyl6(R),7(R)-aziridino-6-deamino-7-deoxy-α-thiolincosaminide in 50 ml. ofisopropyl alcohol is added to the above mixture, and the mixture allowedto stir without replenishing the coolant. The aziridine dissolves duringthe course of circa 10 minutes. The solvent is removed on a rotaryevaporator at 40° C. under 7 mm. of mercury and the residue is dissolvedin methanol and the solution made basic (circa pH 10) by addition of 6Nsodium hydroxide. After about 1 hour, solvent is removed as above andthe residue is partitioned between methylene chloride and water. Themethylene chloride extract is washed with water and dried over anhydroussodium sulfate. Removal of the solvent gives an amorphous solid (5.08grams, 100 percent of theory) of methylN-[1-carbobenzoxy-trans-4-propyl-L-prolyl]-6(R),7(R)-aziridino-6-deamino-7-deoxy-α-thiolincosaminide. Structure of theproduct is confirmed by the infra-red spectrum which shows the 1,700cm⁻¹ absorption of an acylaziridine.

EXAMPLE 2 MethylN-acetyl-2,3,4-tri-O-acetyl-7-deoxy-7(S)-(2-acetoxymethylthio)-ethylthio-.alpha.-thiolincosaminide.

An appropriate reaction vessel is charged with 5.0 grams (1 molarequivalent) of methyl 2,3,4-tri-O-acetyl-6(R),7(R)-acetylaziridino-6-deamino-7-deoxy-α-thiolincosaminide (preparedaccording to the method of Example 19, Part 19-A, U.S. Pat. No.3,671,647), 50 grams of 1,3-dithiolane and 5.25 grams (5.0 ml.; 7 molarequivalents) of glacial acetic acid. The resulting mixture is heated forabout twenty hours in an oil bath maintained at a temperature of about100° C. At the end of this period, the reaction mixture is distilled ata temperature of 100° C. and under pressure of 7 mm. of mercury. Thesolid residue is partitioned between water and methylene chloride. Theorganic layer is separated and washed with saturated aqueous sodiumbicarbonate and then with water. The washed solution is dried overanhydrous sodium sulfate. The dried material is counter-currentdistributed in the system ethanol-water-ethyl acetate-cyclohexane(1:1:1:3,v/v/v/v) to obtain methylN-acetyl-2,3,4-tri-O-acetyl-7-deoxy-7(S)-(2-acetoxymethylthio)ethylthio-.alpha.-thiolincosaminideat a K value of 0.98. Recrystallized from ethyl acetate Skellysolve B¹,there is obtained 5.83 grams (83 percent of theory) of the product inthe form of colorless needles, M.P. 164° C. - 165° C., [α]_(D) ²⁵ =+167° (C, 0.97, CHCl₃).

Anal. Calcd. for: C₂₂ H₃₅ NO₁₀ S₃ (percent): C, 46.38; H, 6.19; N, 2.46;S, 16.89; M.W., 569

Found (percent): C, 46.07; H, 6.18; N, 2.29; S, 16.85; M.W. (Mass Spec.,M⁺) 569.

Similarly, following the above procedure, but replacing the1,3-dithiolane as used therein with equal molar proportions of thefollowing sulfur compounds of formula (IV); 1,3-oxathiane,5-hydroxy-1,3-dithiane, 4-hydroxymethyl-1,3-dithiolane and4-(6-hydroxyhexyl)-1,3-dithiolane, respectively, there is obtainedmethylN-acetyl-2,3,4-tri-O-acetyl-7-deoxy-7(S)-(3-acetoxymethoxy)propylthio-.alpha.-thiolincosaminide,methylN-acetyl-2,3,4-tri-O-acetyl-7-deoxy-7(S)-(3-acetoxymethylthio-2-hydroxypropylthio)-α-thiolincosaminide,a mixture of methylN-acetyl-2,3,4-tri-O-acetyl-7-deoxy-7(S)-(2-acetoxymethylthio-3-hydroxypropylthio)-α-thiolincosaminideand methylN-acetyl-2,3,4-tri-O-acetyl-7-deoxy-7(S)-(3-acetoxymethylthio-1-hydroxypropyl-2-thio)-α-thiolincosaminideand a mixture of methylN-acetyl-2,3,4-tri-O-acetyl-7-deoxy-7(S)-(2-acetoxymethylthio-8-hydroxyoctylthio)-α-thiolincosaminideand methylN-acetyl-2,3,4-tri-O-acetyl-7-deoxy-7(S)-(1-acetoxymethylthio-8-hydroxyoctyl-2-thio)-α-thiolincosaminide,respectively. The above isomeric mixtures are readily separated intotheir isomer component parts by conventional methods, such as bychromatographic techniques, when separation is desired.

EXAMPLE 3 MethylN-acetyl-2,3,4-tri-O-acetyl-7-deoxy-7(S)-(3-acetoxymethylthio)-propylthio-α-thiolincosaminide.

An appropriate reaction vessel is charged with 5.0 grams (1 molarequivalent) of methyl 2,3,4-tri-O-acetyl-6(R),7(R)-acetylaziridino-6-deamino-7-deoxy-α-thiolincosaminide (supra.) and50 grams of 1,3-dithiane. The mixture is heated until molten. To themolten mixture there is added 5.25 grams (5.0 ml., 7 molar equivalents)of glacial acetic acid and the reaction mixture is then stirred whilewarmed in an oil bath maintained at a temperature of 100° C. for about20 hours. At the end of this period, the reaction mixture is allowed tocool, methanol (75 ml.) is added and the crystalline 1,3-dithiane whichseparates (24.5 gm.) is removed by filtration. The filtrate isevaporated to dryness on a rotary evaporator at 40° C. (7 mm. of mercurypressure). The dry residue is chromatographed on silica gel (3 Kg.column, 10.5 cm × 72 cm.) in ethyl acetate-Skellysolve-B (supra.)(1:1,v/v) to remove unreacted 1,3-dithiane residues (total eluate 9.5liters). The eluant is then changed to ethyl acetate to strip thecolumn. An aliquot of the final eluate shows, by thinlayerchromatography, a major material with traces of contaminants of lowerR^(f).

Counter-current distribution of the final eluate in ethanol-water-ethylacetate-cyclohexane (1:1:1:3,v/v/v/v) gives methylN-acetyl-2,3,4-tri-O-acetyl-7-deoxy-7(S)-(3-acetoxymethylthio)propylthio-.alpha.-thiolincosaminideat a K value of 1.29. Recrystallization from ethyl acetate-Skellysolve-B(1:1,v/v) gives 4.97 grams (69 percent of theory) of the product in theform of colorless prisms, M.P. 131.5° C. - 132.5° C; [α]_(D) ²⁵ = +164°(C. 0.94, CHCl₃)

Anal. Calcd. for: C₂₃ H₃₇ NO₁₀ S₃ (percent): C, 47.32; H, 6.39; N, 2.40;S, 16.48; M.W. 583

Found (percent): C, 47.49; H, 6.40; N. 2.04; S, 16.20; M.W. (Mass.Spec., M⁺) 583

EXAMPLE 4 MethylN-acetyl-2,3,4-tri-O-acetyl-6-deoxy-7(S)-(2-acetoxymethoxy)-ethyl-thio-.alpha.-lincosaminide.

An appropriate vessel is charged with 5.0 grams (1 molar equivalent) ofmethyl 2,3,4-tri-O-acetyl-6(R),7(R)-acetylaziridino-6-deamino-7-deoxy-α-thiolincosaminide (supra.), 50grams of 1,3-oxathiolane and 5.25 grams (5.0 ml; 7 molar equivalents) ofglacial acetic acid. The resulting mixture is heated for about 20 hoursin an oil bath maintained at a temperature of about 100° C. At the endof this period, the reaction mixture is distilled at a temperature of100° C. and under a pressure of 7 mm. of mercury. The solid residue ispartitioned between water and methylene chloride. The organic layer isseparated and washed with saturated aqueous sodium bicarbonate and thenwith water. The washed solution is dried over anhydrous sodium sulfate.The residue obtained from the dried solution by removal of solvent iscounter-current distributed in the system ethanol-water-ethylacetate-cyclohexane (1:1:1:2,v/v/v/v) to obtain methylN-acetyl2,3,4-tri-O-acetyl-7-deoxy-7(S)-(2-acetoxymethoxy)ethylthio-.alpha.-thiolincosaminideat a K value of 0.70. Recrystallized from ethylacetate-Skellysolve-B(1:1,v/v), 5.7 grams (83 percent of theory) of the product is obtainedin the form of colorless needles, M.P. 148° C. - 149° C., [α]_(D) ²⁵ =+158° (C, 1.01; CHCl₃).

Anal. Calcd. for: C₂₂ H₃₄ NO₁₁ S₂ (percent): C, 47.72; H, 6.37; N, 2.53;S, 11.58; M.W. 553

Found (percent): C, 47.91; H, 6.50; N, 2.40; S, 11.37; M.W. (Mass Spec.,M⁺) 553

EXAMPLE 5 MethylN-acetyl-2,3,4-tri-O-acetyl-7-deoxy-7(S)-(3-acetoxymethoxy-2-hydroxypropyl)thio-α-thiolincosaminideand methyl

N-acetyl-2,3,4-tri-O-acetyl-7-deoxy-7(S)-(2-acetoxymethoxy-3-hydroxypropyl)thio-α-thiolincosaminide.

To 50 grams of the mixture of 5-hydroxy-1,3-oxathiane and5-hydroxymethyl-1,3-oxathiolane obtained in Preparation 1., supra.,there is added with stirring 10.0 grams of methyl2,3,4-tri-O-acetyl-6(R),7(R)-acetylaziridino-6-deamino-7-deoxy-α-thiolincosaminide (supra), and5.25 grams (5.0 ml., 3.5 molar equivalents) of glacial acetic acid. Theresulting solution is heated for circa 20 hours in an oil bathmaintained at a temperature of circa 100° C. Volatile material is thenremoved by distillation at a temperature of 100° C. under a pressure of<1 mm. of mercury. The solid residue is partitioned between water andmethylene chloride, and the washed methylene chloride extract dried overanhydrous sodium sulfate. Removal of the solvent gives a solid residuewhich is subjected to counter-current distribution in the systemethanol-water-ethyl acetate-cyclohexane (1:1:1:0.5,v/v/v/v) to obtain3.75 grams (52 percent of theory) of a mixture of methylN-acetyl-2,3,4-tri-O-acetyl-7-deoxy-7(S-(3-acetoxymethoxy-2-hydroxy-propylthio-α-thiolincosaminideand methyl N-acetyl-2,3,4-tri-O-acetyl-7-deoxy-7(S)-(2-acetoxymethoxy-3-hydroxypropyl)-thio-α-thiolincosaminideat a K value of 1.14. While the materials are present as a well-definedpeak, thin-layer chromatography reveals the presence of the twomaterials in about equal proportions.

EXAMPLE 6N-(1-carbobenzoxy-trans-4-propyl-L-prolyl)-7-dexoy-7(S)-(2-acetoxymethoxy)-ethylthio-α-thiolincosaminide,

To 5.0 grams of methylN-(1-carbobenzoxy-trans-4-propyl-L-prolyl)-6-7-aziridino-6-deamino-7-deoxy-αthiolincosaminide(prepared according to Example 1., supra.) there is admixed 50 grams of1,3-oxathiolane and 4.2 grams (4.0 ml.; 7 molar equivalents) of glacialacetic acid.

The resulting solution is heated in an oil-bath at 100° C. with magneticstirring for 20 hours. At the end of this time, thin-layerchromatography (silica gel; methanol-chloroform, 1:7 v/v) of an aliquotof the reaction mixture shows the absence of the startingthiolincosaminide material (R_(f) 0.51) and the generation of a new zoneof product (R₄ 0.57). The reaction mixture obtained is chromatographedon silica (1,200 grams, column dimensions 5.8 × 93 cm.). Elution isconducted with the solvent system ethyl acetate-Skellysolve-B, 3:1 v/vuntil 1,500 mls. of eluate has been collected, and then the solventsystem is altered to ethyl acetate-Skellysolve-B-methanol (3:1:0.2,v/v/v) collecting 50 ml. fractions throughout.

Combination of fractions, Nos. 261-340, inclusive, and removal of thesolvent under the standard conditions gives 4.10 grams (63 percent oftheory) of methylM-1-carbobenzoxy-trans-4-propyl-L-prolyl)-7-deoxy-7(S)-(2-acetoxymethoxy)-ethylthio-α-thiolincosaminidein the form of a syrup. Structure of the product is confirmed by nuclearmagnetic resonance analysis which shows the characteristic absorptionspectra of the substituted side chain, and by infrared analysis whichshows a characteristic absorption at 1,740 cm⁻¹ and 1,660 cm⁻¹.

EXAMPLE 7 MethylN-(trans-4-propyl-L-prolyl)-7-deoxy-7(S)-(2-acetoxymethoxy)ethylthio-.alpha.-thiolincosaminide.

An appropriate vessel is charged with 2.87 grams of methylN-(1-carbobenzoxy-trans-4-propyl-L-prolyl)-7-deoxy-7(S)-(2-acetoxymethoxy)ethylthio-α-thiolincosaminide(Example 6, supra) and 1.5 grams of 10 percent palladium on charcoal.The mixture is hydrogenated at an initial pressure of 50 p.s.i. ofhydrogen at room temperature for 24 hours. At the end of this period,thin-layer chromatography (silica gel, ethylacetate-Skellysolve-B-methanol, 3:1:0.2 v/v/v) of an aliquot of thereaction mixture shows the absence of the starting carbobenzoxy compound(R_(f) 0.35) and the presence of a new zone at the origin (i.e., R_(f)0.0). Thin-layer chromatography of the reaction solution on silica gelin the solvent system (methanol-chloroform, 1:5 v/v) shows methylN-(trans-4-propyl-L-propyl)-7-deoxy-7(S)-(2-acetoxymethoxy)ethylthio-α-thiolincosaminide at R_(f)0.42.

The following example illustrates the use of the compounds (II) of theinvention as intermediates in the preparation of compounds having knownvalue and usefulness.

EXAMPLE 8

To 3.75 grams of the mixture of methylN-acetyl-2,3,4-tri-O-acetyl-7-deoxy-7(S)-(2-acetoxymethoxy-3-hydroxypropyl)thio-α-thiolincosaminideand methylN-acetyl-2,3,4-tri-O-acetyl-7-deoxy-7(S)-(3-acetoxymethoxy-2-hydroxypropyl)-thio-α-thiolincosaminideobtained in Example 5, supra.) there is added 100 grams of hydrazinehydrate. The resulting mixture is heated under gentle reflux in an oilbath maintained at 140° C for about 22 hours. At the end of this period,excess hydrazine hydrate is distilled under vacuum and the residuecrystallized from 10 ml. of methanol-acetonitrile mixture to obtain 2.21grams (100 percent of theory; 26 percent of theory based on startingmethyl N-acetyl-2,3,4-tri-O-acetyl-6(R)-, 7(R)-aziridino-6-deamino-7-deoxy-α-thiolincosaminide) ofmethyl-7-deoxy-7(S)-(2,3-dihydroxypropylthio)-α-thiolincosaminide, inthe form of colorless prisms, M.P. 158° C. to 159° C.

EXAMPLE 9

This Example is not an example of the invention, but follows theprocedure of Example 25 in Iranian Pat. 10,395 and by comparison toExamples 5 and 8 herein, shows, the improved product yield obtained bythe process of this invention.

A mixture of 5.0 grams (1 molar equivalent) methylN-acetyl-2,3,4-tri-O-acetyl-6(R),7(R)-aziridino-6-deamino-7-deoxy-α-thiolincosaminide, 50 ccs. of2,3-dihydroxypropyl methyl sulfide, and 5.25 grams (7 molar equivalents)glacial acetic acid is heated in a Pyrex sealed tube for 20 hours in asteam-bath. Volatile materials are removed from the reaction mixture bydistillation at 100° C., the residue is dissolved in methylene chlorideand stirred with an excess of saturated aqueous sodium bicarbonate.Washing of the organic layer with water, drying over anhydrous sodiumsulfate, and removal of the solvent on a rotary evaporator at 40°/7 mm.gives a solid.

Counter-current distribution of this solid in the system 1 ethanol: 1water: 1.5 ethyl acetate: 0.5 cyclohexane (v/v/v/v) gives 1.02 grams(16.2 percent of theory) of methylN-acetyl-2,3,4-tri-O-acetyl-7-deoxy-7(S)-(2,3-dihydroxypropyl)thio-α-thiolincosaminideat a K value of 0.91, as colorless platelets from ethyl acetate; m.p.255° C. - 257° C. [α]_(D) ²⁵ = + 164° (C, .67, chloroform)

To 900 mg. of the acylated product so obtained, there is added 100 ml.of hydrazine hydrate. The mixture is stirred and heated under gentlereflux in an oil bath at 160° C. for 22 hours. Removal of the volatilematerial from the colorless solution by distillation from the oil bathat 110° C./7 mm. gives 600 mg. (circa 100 percent of theory) of methyl7-deoxy-7(S)-(2,3-dihydroxypropylthio)-α-thiolincosaminide, M.P. 158° C.to 159° C. (overall yield based on starting methylN-acetyl-2,3,4-tri-O-acetyl-6(R),7(R)-aziridino-6-deamino-7-deoxy-α-thiolincosaminideis circa 16.6 percent of theory).

EXAMPLE 10 MethylN-(1-methyl-trans-4-propyl-L-prolyl)-6(R),7(R)-aziridino-6-deamino-7-deoxy-α-thiolincosaminide.

1-Methyl-trans-4-propyl-L-proline hydrochloride (4.41 gm., 1 molarequivalent) is suspended in acetonitrile (100 ccs.) with stirring atroom temperature, and triethylamine (4.3 gm., 5.9 ml., 2 molarequivalents) is added to the suspension. The resulting solution is thencooled to -5° in an ice-methanol bath. A precipitate of triethylammoniumchloride appears. Isobutyl chloroformate (2.9 gm., 2.79 ml., 1 molarequivalent) is added to the last mixture at such a rate that thetemperature of the reaction mixture remains between -5° C. and 0° C. andthe resultant mixture is stirred at a temperature of -5° C. for anadditional 5 minutes. A slurry of 5.0 gm. (1 molar equivalent) of methyl6(R),7(R)-aziridino-6-deamino-7-deoxy-α-thiolincosaminide in isopropylalcohol (120 ccs.) is added, and the reaction mixture stirred andallowed to warm to room temperature. After 2 hours, thin-layerchromatography shows the absence of aziridine starting reactant (R_(f)0.09) and the appearance of a new zone of R₅ 0.31. Removal of volatilesolvents on a rotary evaporator at 40° and 7 mm. of mercury give aresidual syrup containing methylN-[1-methyl-trans-4-propyl-L-prolyl]-6(R),7(R)-aziridino:6-deamino-7-deoxy-α-thiolincosaminide.

The latter compound is separated from the syrup residue, when separationis desired, by first dissolving said residue in methylene chloride. Theresulting solution is made mildly alkaline, preferably to a pH of circa8.3 by the addition of aqueous sodium bicarbonate. The resulting mixtureis shaken and the organic phase separated. The organic phase, afterseparation, is washed with water, dried and evaporated to give purifiedmethylN-(1-methyl-trans-4-propyl-L-prolyl)-6(R),7(R)-aziridino-6-deamin-7-deoxy-α-thiolincosaminide,which is useful as an intermediate for preparing the correspondinglincomycin.

Similarly, following the above procedure but replacing the1-methyl-trans-4- propyl-L-proline hydrochloride as used therein with anequal molar proportion of 1-n-hexyl-4-propyl-L-proline hydrochloridethere is obtained methylN-(1-n-hexyl-4-propyl-L-prolyl)-6(R),-7(R)-aziridino-6-deamino-7-deoxy-.alpha.-thiolincosaminide.

EXAMPLE 11 MethylN-(1-methyl-trans-4-propyl-L-prolyl)-7-deoxy-7(S)-(2-acetoxymethoxy)-ethylthio-α-thiolincosaminide.

Without separating the methylN-(1-methyl-trans-4-propyl-L-prolyl)-6(R),7(R)-aziridino-6-deamino-7-deoxy-α-thiolincosaminidefrom the residual syrup last described in Example 10., supra., saidresidual syrup is admixed with 65 grams (34 molar equivalents) of1,3-oxathiolane and the mixture is stirred and heated in an oil-bath at100° C. until the reaction mixture is a solution. Glacial acetic acid(8.9 gm., 7 molar equivalents) is then added to the solution and heatingis maintained for 18 hours. At the end of this period, volatile materialis removed from the reaction solution by distillation from the oil-bathat 100° under diminished pressure to give a syrupy residue, showing amajor product by thin-layer chromatography (silica gel,methanol-chloroform, 1:7 v/v), R_(f) 0.49, which is methylN-(1-methyl-trans-4-propyl-L-prolyl)-7-deoxy-7(S)-(2-acetoxymethoxy)-ethylthio-α-thiolincosaminide.The latter compound may be separated from the residue in pure form, whendesired, by conventional methods for example by chromatography andcounter-current distribution.

Similarly, following the above procedure but replacing the syrup residuecontaining methylN-(1-methyl-trans-4-propyl-L-prolyl)-6(R),7(R)-aziridino-6-deamino-7-deoxy-α-thiolincosaminideas used therein with methylN-(1-n-hexyl-4-propyl-L-prolyl)-6(R),7(R)-aziridino-6-deamino-7-deoxy-.alpha.thiolincosaminide,there is obtained methylN-(1-n-hexyl-4-propyl-L-prolyl)-7-deoxy-7(S)-(2-acetoxymethoxy)-ethylthio-α-thiolincosaminide.

EXAMPLE 12

This example is not an example of the invention but illustrates thehydrolysis of compounds (IX) of the invention to obtain usefulantibacterial agents.

Without separating the methylN-(1-methyl-trans-4-propyl-L-prolyl-7-deoxy-7(S)-(2-acetoxymethoxy)-ethylthio-α-thiolincosaminidefrom the syrupy residue last described in Example 11., supra., saidsyrup residue is dissolved in methanol (50 ml.), adjusted to a pH ofabout 10 by the addition of aqueous sodium hydroxide (1N), and allowedto stand at room temperature for 11/2 hours. Methanol is then removedfrom the alkaline solution on a rotary evaporator at 40° C. under 7 mm.of mercury, and the residual aqueous layer is extracted with chloroform.The extract is dried over anhydrous sodium sulfate. Removal of solventson a rotary evaporator at 40° under 7 mm. of mercury gives a colorlesssyrup, (7.69 gm.9. Chromatography on silica gel (1,200 gm. columndimensions 5.8 × 91 cm.) is conducted with methanol-methylene chloride,(1:12 v/v) and 50 cc. fractions are collected. Fractions 114-214,inclusive, are pooled and solvent stripped from the combined fractionsto give a syrup residue which is 7-deoxy-7(S)-(2-hydroxyethylthio)lincomycin, a useful antibacterial agent; seeIranian Pat. No. 10,407.

EXAMPLE 13 MethylN-[trans-4-propyl-L-prolyl]-6(R),7(R)-aziridino-6-deamino-7-deoxy-α-thiolincosaminide.

To a solution of 5.08 grams (10 moles) of methylN-[1-carbobenzoxy-trans-4-propyl-L-prolyl]-6(R),7(R)-aziridino-6-deamino-7-deoxy-α-thiolincosaminide(Example 1, supra.) in 200 ml. of methanol, there is added 0.50 grams of10% palladium on carbon. The mixture is charged to a Parr low pressurehydrogenation vessel and agitated for about 24 hours under a hydrogengas atmosphere at a pressure of about 50 psi (gauge); at the end of thisperiod, the reaction mixture is filtered and the solvent removed byevaporation. The residue is a crude mixture containing methylN-[trans-4-propyl-L-prolyl]-6(R),7(R)-aziridino-6-deamino-7-deoxy-α-thiolincosaminide.When desired, the methylN-[trans-4-propyl-L-prolyl]-6(R),7(R)-aziridino-6-deamino-7-deoxy-αthioloicosaminidemay be separated from the crude mixture by conventional methods ofseparation. For example, the mixture may be dissolved in methanol,filtered to remove solid residues, and the filtrate made mildlyalkaline, preferably to a pH of circa 8.3 by the addition of base,preferably sodium bicarbonate. The alkaline solution is then evaporatedand the residue partitioned between methylene chloride and water. Themethylene chloride extract upon washing with water, drying andevaporation of solvent yields methylN-[trans-4-propyl-L-propyl]-6(R),7(R)-aziridino-6-deamino-7-deoxy-α-thiolincosaminidein purified form.

EXAMPLE 14 MethylN-(trans-4-propyl-L-prolyl)-7-deoxy-7(S)-(2-acetoxymethoxy)-ethylthio-.alpha.-thiolincosaminide.

The crude mixture containing methylN-(trans-4-propyl-L-prolyl)-6(R),7(R)-aziridino-6-deamino-7-deoxy-α-thiolincosaminideas obtained in Example 13., supra., is admixed with 27.0 grams (300mmols) of 1,3-oxathiolane and heated in an oil bath at 100° C. until themixture is a solution. To the solution there is added 4.2 grams (70mmoles) of glacial acetic acid and the resulting mixture is stirred forabout 18 hours while maintaining the temperature of the reaction mixtureat about 100° C. At the end of this period, solvent is stripped from thereaction mixture to obtain a product residue which is crude methylN-(trans-4-propyl-L-propyl)-7-deoxy-7(S)-(2-acetoxymethoxy)-ethylthio-.alpha.-thiolincosaminde.

The product is readily purified by conventional chromatographic methodsto give purified methylN-(trans-4-propyl-L-prolyl)-7-deoxy-7(S)-(2-acetoxymethoxy)-ethylthio-.alpha.-thiolincosaminide.

Compounds (I) of the invention having the specific formula: ##STR31##wherein L is selected from hydrogen and lower alkyl, R₄ and R₅ are eachlower alkyl and Y is selected from hydrogen and carboxacyl areparticularly valuable intermediates for the synthesis of a wide varietyof lincomycin analogs. For example, the compounds (XVI) of the inventionmay be substituted for alkylN-acyl-6(R),-7(R)-aziridino-6-deamino-7-deoxy-α-thiolincosaminides inthe processes of U.S. Pat. Nos. 3,544,551; 3,671,647; 3,702,322; IranianPat. Nos. 10,395; 10,407 and 10,460, supra. Such a substitution yieldsas a product of said processes, the respective lincomycin analogs, thusobviating the necessity of removing the N-carboxacyl group and replacingit with the N-L-2-pyrrolidinecarboxyacyl group when the lincomycinderivative is the .[.ultrimate.]. .Iadd.ultimate .Iaddend.productdesired. This advantage is of particular importance in those instanceswherein removal of an N-carboxacyl blocking group may occur concurrentlywith the undesired removal of an acyl group from another portion of thethiolincosaminide molecule. For example, when in a compound (II) of theinvention wherein Ac₁ and D are both carboxacyl groups, it may bedesirable to replace the Ac₁ carboxacyl group with anL-2-pyrrolidinecarboxylic group while retaining the carboxacyl group D.This may be accomplished by employing the appropriate compound (XVI) asthe starting reactant (III) in Process A, supra.

I claim:
 1. A compound of the formula: ##STR32## wherein R₁ when takenindependently represents hydrogen; R₂ when takene independentlyrepresents the monovalent moiety ##STR33## wherein Ac is selected fromcarboxyacyl of from 2 to 18 carbon atoms, inclusive, and an acyl radicalof formula: ##STR34## wherein Z is selected from hydrogen, lower alkyland an amino protecting group removable by hydrogenolysis; R₅ is loweralkyl; R₁ and R₂ when taken together form the divalent group of theformula: ##STR35## wherein Z and R₅ are as defined above; R₃ is hydrogenwhen R₁ and R₂ are taken together and when R₁ and R₂ are takenindependently, R₃ is a monovalent thio group in the 7(S)-position,having the formula: ##STR36## wherein A is selected from hydrogen andhydroxy, B is selected from hydrogen and monohydroxyloweralkyl, n is theinteger 0 when B is monohydroxyloweralkyl and an integer of from 0 to 1when B is hydrogen, X is .[.selected from.]. oxygen .[.and sulfur.]., Dis an acyl radical of a lower hydrocarbon carboxylic acid; R₄ representslower alkyl; and Y is selected from carboxacyl of from 2 to 18 carbonatoms, inclusive, and hydrogen.
 2. A compound of the formula: ##STR37##wherein A is selected from hydrogen and hydroxyl; B is selected fromhydrogen and monohydroxyloweralkyl; n is the integer 0 when B ismonohydroxyloweralkyl and n is an integer of from 0 to 1, inclusive,when B is hydrogen; X is .[.selected from.]. oxygen .[.and sulfur.].; Dis the acyl radical of a lower hydrocarbon carboxylic acid; Ac₁ isselected from carboxacyl of from 2 to 18 carbon atoms, inclusive, and anacyl radical of the formula: ##STR38## wherein Z is selected fromhydrogen, lower alkyl and an amino protecting group removable byhydrogenolysis; and R₅ is lower alkyl; R₄ represents lower alkyl; and Yis selected from carboxacyl of from 2 to 18 carbon atoms, inclusive, andhydrogen.
 3. A process for preparing compounds of the formula: ##STR39##wherein A is selected from hydrogen and hydroxy; B is selected fromhydrogen and monohydroxyloweralkyl; n is the integer 0 when B ismonohydroxyloweralkyl and n is an integer of from 0 to 1, inclusive,when B is hydrogen; X is .[.selected from.]. oxygen .Iadd..[.andsulfur.]..Iaddend.; D is the acyl radical of a lower hydrocarboncarboxylic acid; Ac₁ is selected from carboxyacyl of from 2 to 18 carbonatoms, inclusive, and an acyl radical of formula: ##STR40## wherein G isselected from lower alkyl and an amino protecting group removable byhydrogenolysis and R₅ is lower alkyl; R₄ represents lower alkyl; and Yis selected from carboxacyl of from 2 to 18 carbon atoms, inclusive, andhydrogen, which comprises bringing together
 1. the corresponding alkylN-acyl-6,7-aziridino-6-deamino-7-deoxy-α-thiolincosaminide of formula:##STR41## wherein AC₁, R₄ and Y are as defined above;
 2. an anhydrouslower hydrocarbon carboxylic acid; and3. a corresponding sulfur compoundof formula: ##STR42## wherein X, A, B, and n are as defined above.
 4. Acompound of the formula: ##STR43## wherein A is selected from hydrogenand hydroxyl; B is selected from hydrogen and monohydroxyloweralkyl; nis the integer 0 when B is monohydroxyloweralkyl and n is an integer offrom 0 to 1, inclusive, when B is hydrogen; X is .[.selected from.].oxygen .[.and sulfur.].; D is the acyl radical of a lower hydrocarboncarboxylic acid; Y is selected from carboxacyl of from 2 to 18 carbonatoms, inclusive, and hydrogen; R₄ and R₅ are each lower alkyl.
 5. Acompound according to claim 4 which is methylN-(trans-4-propyl-L-prolyl)-7-deoxy-7(S)-(2-acetoxymethoxy)-ethylthio-.alpha.-thiolincosaminide.6. A compound of the formula: ##STR44## wherein A is selected fromhydrogen and hydroxyl; B is selected from hydrogen andmonohydroxyloweralkyl; n is the integer 0 when B ismonohydroxyloweralkyl and n is an integer of from 0 to 1, inclusive,when B is hydrogen; X is .[.selected from.]. oxygen .[.and sulfur.].; Yis selected from carboxacyl of from 2 to 18 carbon atoms, inclusive, andhydrogen, R₄, R₅ and R₆ are each lower alkyl.
 7. A compound according toclaim 6 wherein Y is hydrogen.
 8. A compound according to claim 6 whichis methylN-(1-methyl-trans-4-propyl-L-prolyl)-7-deoxy-7(S)-(2-acetoxymethoxy)-ethylthio-α-thiolincosaminide.9. A compound of the formula: ##STR45## wherein G is selected from loweralkyl and an amino protecting group removable by hydrogenolysis; R₄ andR₅ each represent lower alkyl and Y is selected from carboxacyl of from2 to 18 carbon atoms, inclusive, and hydrogen.
 10. The compound of claim9 wherein Y is hydrogen.
 11. A compound according to claim 9 which ismethylN-(1-carbobenzoxy-trans-4-propyl-L-prolyl)-6,7-aziridino-6-deamino-7-deoxy-α-thiolincasminide.12. A process for preparing compounds of the formula: ##STR46## whereinG is selected from lower alkyl and an amino protecting group removableby hydrogenolysis; R₄ and R₅ are each lower alkyl, Y is selected fromcarboxacyl of from 2 to 18 carbon atoms, inclusive, and hydrogen whichcomprises N-acylating a thiolincosaminide compound of formula: ##STR47##wherein Y and R₄ are as defined above; with a mixed anhydride offormula: ##STR48## wherein G and R₅ are as defined above; b is aninteger of from 1 to 3, at a temperature of from about -10° C. to 5° C.13. A process according to claim 12 wherein said thiolincosaminide issolubilized in an aliphatic alcohol having a molecular weight of atleast about 60 prior to N-acylation.
 14. A process according to claim 12wherein said thiolinocosaminide compound reactant is methyl6(R),7(R)-aziridino-6-deamino-7-deoxy-α-thiolincosaminide, said mixedanhydride in N-[1-carbobenzoxy-trans-4-propyl-L-prolyl]-butylcarbonicanhydride and the product of the process is methylN-[1-carbobenzoxy-trans-4-propyl-L-propyl-6(R),7(R)-aziridino-6-deamino-7-deoxy-α-thiolinocosaminide.15. A process for preparing compounds of the formula: ##STR49## whereinG is selected from lower alkyl and a amino protecting group removable byhydrogenolysis; R₄ and r₅ are each lower alkyl; Y is selected fromhydrogen and carboxacyl of from 2 to 18 carbon atoms, inclusive; A isselected from hydrogen and hydroxyl; B is selected from hydrogen andmonohydroxyloweralkyl; n is the integer 0 when B ismonohydroxyloweralkyl and n is an integer of from 0 to 1, inclusive,when B is hydrogen; X is .[.selected from.]. oxygen .[.and sulfur.].,and D is the acyl radical of a lower hydrocarbon carboxylic acid, whichcomprises:
 1. reacting together an appropriate aziridine of formula:##STR50## wherein Y and R₄ are as defined above; and an appropriatemixed anhydride of formula: ##STR51## wherein G and R₅ are as previouslydefined and b is an integer of from 1 to 3, inclusive; at a temperatureof from about -10° C. to about 5° C.;
 2. warming the reaction mixture soobtained to a temperature of from about 25° C. to about 180° C.; and3.adding to said warmed reaction mixture (I) an appropriate sulfurcompound of the formula: ##STR52## wherein A, B, X and n are as definedabove and (II) an anhydrous lower hydrocarbon carboxylic acid.
 16. Theprocess of claim 15 wherein methyl6(R),7(R)-aziridino-6-deamino-7-deoxy-α-thiolincosaminide is reactedwith N-[1-carbobenzoxy-trans-4-propyl-L-prolyl]-butylcarbonic anhydridein step (1.) and the product thereof is added to 1,3-oxathiolane andacetic acid in step (3.) whereby there is obtained) methylN-(1-carbobenzoxy-trans-4-propyl-L-prolyl)-7-deoxy-7(S)-(2-acetoxymethoxy)-ethylthio-α-thiolincosaminide.17. A process for preparing compounds of the formula: ##STR53## whereinR₄ and R₅ each represent lower alkyl; Y is selected from carboxacyl offrom 2 to 18 carbon atoms, inclusive, and hydrogen; A is selected fromhydrogen and hydroxy; B is selected from hydrogen andmonohydroxyloweralkyl; n is the integer 0 when B ismonohydroxyloweralkyl and n is an integer of from 0 to 1, inclusive,when B is hydrogen; X is .[.selected from.]. oxygen .[.and sulfur.].;and D is the acyl radical of a lower hydrocarbon carboxylic acid, whichcomprises:
 1. reacting together in appropriate aziridine compound offormula: ##STR54## wherein Y and r₄ are as defined above; and anappropriate mixed anhydride of formula: ##STR55##wherein R₅ is asdefined above, J is an amino protecting group removable byhydrogenolysis and b is an integer of from 1 to 3, inclusive; at atemperature of from about -10° C. to about 5° C.;
 2. warming thereaction mixture so obtained to a temperature of from about 25° C. toabout 50° C.;3. subjecting said warmed reaction mixture to catalytichydrogenation; and
 4. adding to said hydrogenated mixture (I) anappropriate sulfur compound of the formula: ##STR56## wherein A, B, Xand n are as defined above and (II) an anhydrous lower hydrocarboncarboxylic acid.
 18. A compound of the formula: ##STR57## wherein R₄ andR₅ are each lower alkyl and Y is selected from hydrogen and carboxyacylof from 2 to 18 carbon atoms, inclusive.
 19. A compound according toclaim 18 which is methylN-[trans-4-propyl-L-prolyl]-6(R),7(R)-aziridino-6-deamino-7-deoxy-α-thiolincosaminide.20. A compound according to claim 2 which is methylN-(1-carbobenzoxy-trans-4-propyl-L-prolyl)-7-deoxy-7(S)-(2-acetoxymethoxy)-ethylthio-α-thiolincosaminide.21. A compound according to claim 9 which is methylN-(1-methyl-trans-4-propyl-L-prolyl)-6(R),7(R)-aziridino-6-deamino-7-deoxy-α-thiolincosaminide.